| Year | Rank | Number |
| 2011 | 6453 | 20 |
| 2010 | 4920 | 29 |
| 2009 | 5284 | 27 |
| 2008 | 5522 | 26 |
| 2007 | 4099 | 38 |
| 2006 | 4220 | 35 |
| 2005 | 4658 | 29 |
| 2004 | 4897 | 27 |
| 2003 | 4081 | 33 |
| 2002 | 3698 | 36 |
| 2001 | 5308 | 22 |
| 2000 | 5440 | 21 |
| 1999 | 5585 | 19 |
| 1998 | 4748 | 23 |
| 1997 | 6713 | 14 |
| 1996 | 7008 | 13 |
| 1995 | 6505 | 14 |
| 1994 | 11364 | 7 |
| 1992 | 8517 | 10 |
| 1991 | 11096 | 7 |
| 1990 | 14483 | 5 |
| 1988 | 8943 | 8 |
| 1987 | 10787 | 6 |
| 1985 | 11843 | 5 |
| 1984 | 11562 | 5 |
| 1978 | 10836 | 5 |
| 1974 | 9711 | 5 |